/*! \page Optimize_method2Doc Optimize method2

Keyword: OPTIMIZE2

\section description Description
Uses Levenberg-Marquardt algorithm to minimize wavefunction's
energy/variance or mixture of both. It uses self-adjustable 
damping parameter which is added to the diagonal of corresponding hessian.
Consequently a Newton step is performed to get new parameters.    
(See C. J. Umrigar and C. Filippi.  Phys. Rev. Lett. 94, 150201 (2005) )


\section options Options

\subsection reqopt Required 

<table>
<tr> <td> <b>Option</b> <td> <b>Type</b> <td> <b>Description</b>
<tr> <td> NCONFIG  <td> Integer <td> Number of configurations
<tr> <td> ITERATIONS  <td> Float 
     <td> Number of iterations.  Usually it converges within 10 iterations or so. 
<tr> <td> EREF  <td> Float <td> A best guess at the optimized energy
<tr> <td> READCONFIG <td> String <td> Read configurations from a file
</table>

\subsection optopt Optional

<table>
<tr> <td> <b>Option</b> <td> <b>Type</b> <td> <b> Default </b> 
     <td> <b>Description</b>
<tr> <td> PSEUDOTEMP  <td> String <td> runid.pseudo 
     <td> Choose the filename for the temporary pseudopotential values.  
Should be on a fast disk with lots of space
<tr> <td> WFOUTPUT <td> String <td>  runid.wfout 
     <td> Choose the filename to place an input deck for the final 
wavefunction and intermediate ones as the optimization
continues.
<tr> <td> MINFUNCTION  <td> String <td>  VARIANCE 
     <td> Choose the minimization function.  Options are:
 
VARIANCE (default) : \f$ \sum{(E_l - E_{ref})^2} \f$
 
ENERGY : \f$ \frac{1}{N} \sum { E_l }  \f$

MIXED : \f$ mixing \frac{1}{N} \sum { E_l } + (1-mixing) \sum{(E_l - E_{ref})^2}  \f$

For ENERGY or MIXED, USE_WEIGHTS is automatically turned on.
<tr> <td> USE_WEIGHTS  <td> Keyword <td> off 
     <td> Turn on correlated-sampling type reweighting
<tr> <td> MIXING  <td> Float <td> 0.95 <td> Mixing weight for energy contribution in mixed minimization

</table>

\subsection expopt Experimental 
<table>
<tr> <td> <b>Option</b> <td> <b>Type</b> <td> <b> Default </b> 
     <td> <b>Description</b>
<tr> <td> EXTENDED_WFOUTPUT <td> Keyword <td>  off 
     <td> Turn on printout of wavefunction after each step of optimization
<tr> <td> NFIXED_ITERATIONS <td> Integer <td>  4 
     <td> Number of iterations with number of configurations fixed   
<tr> <td> MULTIPLICATIVE_FACTOR <td> Integer <td>  2 
     <td> Ratio by which the configurations will be increased after NFIXED_ITERATIONS 
<tr> <td> START_NCONFIG <td> Integer <td>  NCONFIG 
     <td> Number of starting configurations 
</table>



*/
